With the ongoing development of micro-circuitry and multimedia technology, digital cameras are now in widespread use. High-end portable electronic devices such as mobile phones and PDAs (Personal Digital Assistants) are being developed to be increasingly multi-functional. Many of these portable electronic devices are now equipped with a digital camera. To facilitate portability, designs of such portable electronic devices tend to be compact, slim, and light. Accordingly, digital cameras incorporated in the portable electronic devices have also been required to be reduced in size and weight and also in cost.
In the digital camera equipped with generally coaxial optical systems, optical elements are arranged in the direction of the optical axis. Therefore, there is a limit to the reduction in thickness of the optical systems. At the same time, the number of lens elements unavoidably increases because it is necessary to correct chromatic aberration produced by a refracting lens used in the optical systems. Therefore, it is difficult to reduce the cost, size and weight in the present related art. In addition, since there are a number of lens elements, it is difficult to accurately coaxially assemble the lens elements of the optical system and the assembling process is relative complex as a result.
What is needed, therefore, is an improved digital camera module and a lens used therein which has a minimal number of optical elements and good optical performance.